# -*- coding: utf-8 -*-#
#-------------------------------------------------------------------------------
# 建立者:        博智科技  
# Name:         demo1051
# Description:
# Author:       yzl
# Date:         2019-02-07
#-------------------------------------------------------------------------------

class RigthTriangle:
    def __init__(self):
        self.n = 1

    def __next__(self):
        result = '*' * (2 * self.n - 1)
        self.n += 1
        return result

    def __iter__(self):
        return self


rt = RigthTriangle()

for e in rt:
    if(len(e) > 20):
        break
    print(e)
